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Nysjö, Johan
Publications (10 of 18) Show all publications
Nilsson, J., Nysjö, J., Carlsson, A.-P. & Thor, A. (2018). Comparison analysis of orbital shape and volume in unilateral fractured orbits. Journal of Cranio-Maxillofacial Surgery, 46(3), 381-387
Open this publication in new window or tab >>Comparison analysis of orbital shape and volume in unilateral fractured orbits
2018 (English)In: Journal of Cranio-Maxillofacial Surgery, ISSN 1010-5182, E-ISSN 1878-4119, Vol. 46, no 3, p. 381-387Article in journal (Refereed) Published
Abstract [en]

Facial fractures often result in changes of the orbital volume. These changes can be measured in three-dimensional (3D) computed tomography (CT) scans for preoperative planning and postoperative evaluation. The aim of this study was to analyze the orbital volume and shape before and after surgical treatment of unilateral orbital fractures using semi-automatic image segmentation and registration techniques. The orbital volume in 21 patients was assessed by a semi-automatic model-based segmentation method. The fractured orbit was compared relative to the contralateral orbit. The same procedure was performed for the postoperative evaluation. Two observers performed the segmentation procedure, and the inter- and intraobserver variability was evaluated. The interobserver variability (mean volume difference ± 1.96 SD) was −0.6 ± 1.0 ml in the first trial and 0.7 ± 0.8 ml in the second trial. The intra-observer variability was −0.2 ± 0.7 ml for the first observer and 1.1 ± 0.9 ml for the second observer. The average volume overlap (Dice similarity coefficient) between the fractured and contralateral side increased after surgery, while the mean and maximum surface distance decreased, indicating that the surgery contributed to a re-establishment of size and shape. In conclusion, our study shows that the semi-automatic segmentation method has precision for detecting volume differences down to 1.0 ml. The combination of semi-automatic segmentation and 3D shape analysis provides a powerful tool for planning and evaluating treatment of orbital fractures.

National Category
Surgery Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-341456 (URN)10.1016/j.jcms.2017.12.012 (DOI)000425712500002 ()29325886 (PubMedID)
Available from: 2017-12-21 Created: 2018-02-09 Last updated: 2018-05-03Bibliographically approved
Levasseur, J., Nysjö, J., Sandy, R., Britto, J. A., Garcelon, N., Haber, S., . . . Khonsari, R. H. (2018). Orbital volume and shape in Treacher Collins syndrome. Journal of Cranio-Maxillofacial Surgery, 46(2), 305-311
Open this publication in new window or tab >>Orbital volume and shape in Treacher Collins syndrome
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2018 (English)In: Journal of Cranio-Maxillofacial Surgery, ISSN 1010-5182, E-ISSN 1878-4119, Vol. 46, no 2, p. 305-311Article in journal (Refereed) Published
Abstract [en]

Orbito-palpebral reconstruction is a challenge in Treacher Collins syndrome (TCS). This study investigates orbital phenotypes in TCS using cephalometry and orbital shape analysis. Eighteen TCS and 52 control patients were included in this study, using the Dr Warehouse database. Orbital cephalometry was based on 20 landmarks, 10 planes, 16 angles, and 22 distances. Orbits were segmented. Registration-based, age-specific mean models were generated using semi-automatic segmentation, and aligned and compared using color-coded distance maps - mean absolute distance (MAD), Hausdorff distance (HD), and Dice similarity coefficient (DSC). Symmetry was assessed by mirroring and DSC computing. Central orbital depth ( COD) and medial orbital depth ( MOD) allowed 100% of orbits to be classified. COD and lateral orbital depth (LOD) were different from the controls. Average MAD between TCS and controls was <= 1.5 mm, while for HD it was > 1.5 mm, and for DSC <1. TCS orbits were more asymmetrical than controls, and orbital volumes were smaller when age was considered as a confounding factor, and had a trend for normalization with age. This report emphasizes the importance of combining different morphometric approaches in the phenotype characterization of non-trivial structures such as the orbit, and supports composite skeletal and soft-tissue strategies for the management of the peri-orbital region.

Place, publisher, year, edition, pages
CHURCHILL LIVINGSTONE, 2018
Keywords
Treacher collins, Orbits, Volume, Morphometrics, 3D-cephalometry, Midface
National Category
Surgery
Identifiers
urn:nbn:se:uu:diva-349828 (URN)10.1016/j.jcms.2017.11.028 (DOI)000425711300020 ()29275073 (PubMedID)
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-05-04Bibliographically approved
Nyström, I., Nysjö, J., Thor, A. & Malmberg, F. (2017). BoneSplit – A 3D painting tool for interactive bone segmentation in CT images. In: Pattern Recognition and Information Processing: PRIP 2016. Paper presented at PRIP 2016, October 3–5, Minsk, Belarus (pp. 3-13). Springer
Open this publication in new window or tab >>BoneSplit – A 3D painting tool for interactive bone segmentation in CT images
2017 (English)In: Pattern Recognition and Information Processing: PRIP 2016, Springer, 2017, p. 3-13Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Springer, 2017
Series
Communications in Computer and Information Science ; 673
National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-317762 (URN)10.1007/978-3-319-54220-1_1 (DOI)978-3-319-54219-5 (ISBN)
Conference
PRIP 2016, October 3–5, Minsk, Belarus
Available from: 2017-02-17 Created: 2017-03-17 Last updated: 2017-03-17Bibliographically approved
Christersson, A., Nysjö, J., Berglund, L., Malmberg, F., Sintorn, I.-M., Nyström, I. & Larsson, S. (2016). Comparison of 2D radiography and a semi-automatic CT-based 3D method for measuring change in dorsal angulation over time in distal radius fractures. Skeletal Radiology, 45(6), 763-769
Open this publication in new window or tab >>Comparison of 2D radiography and a semi-automatic CT-based 3D method for measuring change in dorsal angulation over time in distal radius fractures
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2016 (English)In: Skeletal Radiology, ISSN 0364-2348, E-ISSN 1432-2161, Vol. 45, no 6, p. 763-769Article in journal (Refereed) Published
Abstract [en]

Objective The aim of the present study was to compare the reliability and agreement between a computer tomography-based method (CT) and digitalised 2D radiographs (XR) when measuring change in dorsal angulation over time in distal radius fractures. Materials and methods Radiographs from 33 distal radius fractures treated with external fixation were retrospectively analysed. All fractures had been examined using both XR and CT at six times over 6 months postoperatively. The changes in dorsal angulation between the first reference images and the following examinations in every patient were calculated from 133 follow-up measurements by two assessors and repeated at two different time points. The measurements were analysed using Bland-Altman plots, comparing intra- and inter-observer agreement within and between XR and CT. Results The mean differences in intra- and inter-observer measurements for XR, CT, and between XR and CT were close to zero, implying equal validity. The average intra- and inter-observer limits of agreement for XR, CT, and between XR and CT were +/- 4.4 degrees, +/- 1.9 degrees and +/- 6.8 degrees respectively. Conclusions For scientific purpose, the reliability of XR seems unacceptably low when measuring changes in dorsal angulation in distal radius fractures, whereas the reliability for the semi-automatic CT-based method was higher and is therefore preferable when a more precise method is requested.

National Category
Orthopaedics Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-297776 (URN)10.1007/s00256-016-2350-6 (DOI)000374476200003 ()26922189 (PubMedID)
Available from: 2016-02-27 Created: 2016-06-28 Last updated: 2018-05-14Bibliographically approved
Khonsari, R. H., Way, B., Nysjö, J., Odri, G. A., Olszewski, R., Evans, R. D., . . . Britto, J. A. (2016). Fronto-facial advancement and bipartition in Crouzon-Pfeiffer and Apert syndromes: Impact of fronto-facial surgery upon orbital and airway parameters in FGFR2 syndromes. Journal of Cranio-Maxillofacial Surgery, 44(10), 1567-1575
Open this publication in new window or tab >>Fronto-facial advancement and bipartition in Crouzon-Pfeiffer and Apert syndromes: Impact of fronto-facial surgery upon orbital and airway parameters in FGFR2 syndromes
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2016 (English)In: Journal of Cranio-Maxillofacial Surgery, ISSN 1010-5182, E-ISSN 1878-4119, Vol. 44, no 10, p. 1567-1575Article in journal (Refereed) Published
Abstract [en]

A major concern in FGFR2 craniofaciosynostosis is oculo-orbital disproportion, such that orbital malformation provides poor accommodation and support for the orbital contents and peri-orbita, leading to insufficient eyelid closure, corneal exposure and eventually to functional visual impairment. Fronto-facial monobloc osteotomy followed by distraction osteogenesis aims to correct midfacial growth deficiencies in Crouzon–Pfeiffer syndrome patients. Fronto-facial bipartition osteotomy followed by distraction is a procedure of choice in Apert syndrome patients. These procedures modify the shape and volume of the orbit and tend to correct oculo-orbital disproportion. Little is known about the detailed 3D shape of the orbital phenotype in CPS and AS, and about how this is modified by fronto-facial surgery.

Twenty-eight patients with CMS, 13 patients with AS and 40 control patients were included. CT scans were performed before and after fronto-facial surgery. Late post-operative scans were available for the Crouzon–Pfeiffer syndrome group. Orbital morphology was investigated using conventional three-dimensional cephalometry and shape analysis after mesh-based segmentation of the orbital contents.

We characterized the 3D morphology of CPS and AS orbits and showed how orbital shape is modified by surgery. We showed that monobloc-distraction in CPS and bipartition-distraction in AS specifically address the morphological characteristics of the two syndromes.

Keywords
Monobloc-distraction, Orbit, 3D-cephalometry, Crouzon–Pfeiffer syndrome, Apert syndrome, FGFR2
National Category
Surgery Medical Image Processing
Identifiers
urn:nbn:se:uu:diva-311642 (URN)10.1016/j.jcms.2016.08.015 (DOI)000389106700010 ()27639780 (PubMedID)
Available from: 2016-12-30 Created: 2016-12-30 Last updated: 2017-11-29Bibliographically approved
Nysjö, J. (2016). Interactive 3D Image Analysis for Cranio-Maxillofacial Surgery Planning and Orthopedic Applications. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Interactive 3D Image Analysis for Cranio-Maxillofacial Surgery Planning and Orthopedic Applications
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Modern medical imaging devices are able to generate highly detailed three-dimensional (3D) images of the skeleton. Computerized image processing and analysis methods, combined with real-time volume visualization techniques, can greatly facilitate the interpretation of such images and are increasingly used in surgical planning to aid reconstruction of the skeleton after trauma or disease. Two key challenges are to accurately separate (segment) bone structures or cavities of interest from the rest of the image and to interact with the 3D data in an efficient way. This thesis presents efficient and precise interactive methods for segmenting, visualizing, and analysing 3D computed tomography (CT) images of the skeleton. The methods are validated on real CT datasets and are primarily intended to support planning and evaluation of cranio-maxillofacial (CMF) and orthopedic surgery.

Two interactive methods for segmenting the orbit (eye-socket) are introduced. The first method implements a deformable model that is guided and fitted to the orbit via haptic 3D interaction, whereas the second method implements a user-steered volumetric brush that uses distance and gradient information to find exact object boundaries.

The thesis also presents a semi-automatic method for measuring 3D angulation changes in wrist fractures. The fractured bone is extracted with interactive mesh segmentation, and the angulation is determined with a technique based on surface registration and RANSAC.

Lastly, the thesis presents an interactive and intuitive tool for segmenting individual bones and bone fragments. This type of segmentation is essential for virtual surgery planning, but takes several hours to perform with conventional manual methods. The presented tool combines GPU-accelerated random walks segmentation with direct volume rendering and interactive 3D texture painting to enable quick marking and separation of bone structures. It enables the user to produce an accurate segmentation within a few minutes, thereby removing a major bottleneck in the planning procedure.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. p. 58
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1411
Keywords
medical image analysis, interactive segmentation, volume rendering, computed tomography
National Category
Computer Sciences Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-301180 (URN)978-91-554-9668-5 (ISBN)
External cooperation:
Public defence
2016-09-30, ITC 2446, Lägerhyddsvägen 2, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2016-09-09 Created: 2016-08-19 Last updated: 2018-01-10
Schold Linnér, E., Morén, M., Smed, K.-O., Nysjö, J. & Strand, R. (2016). LatticeLibrary and BccFccRaycaster: Software for processing and viewing 3D data on optimal sampling lattices. SoftwareX, 5, 16-24
Open this publication in new window or tab >>LatticeLibrary and BccFccRaycaster: Software for processing and viewing 3D data on optimal sampling lattices
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2016 (English)In: SoftwareX, ISSN 2352-7110, Vol. 5, p. 16-24Article in journal (Refereed) Published
National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-265337 (URN)10.1016/j.softx.2016.01.002 (DOI)
Available from: 2016-03-15 Created: 2015-10-27 Last updated: 2016-12-28Bibliographically approved
Nysjö, J., Malmberg, F., Sintorn, I.-M. & Nyström, I. (2015). BoneSplit - A 3D Texture Painting Tool for Interactive Bone Separation in CT Images. Journal of WSCG, 23(2), 157-166
Open this publication in new window or tab >>BoneSplit - A 3D Texture Painting Tool for Interactive Bone Separation in CT Images
2015 (English)In: Journal of WSCG, ISSN 1213-6972, E-ISSN 1213-6964, Vol. 23, no 2, p. 157-166Article in journal (Refereed) Published
Abstract [en]

We present an efficient interactive tool for separating collectively segmented bones and bone fragments in 3D computed tomography (CT) images. The tool, which is primarily intended for virtual cranio-maxillofacial (CMF) surgery planning, combines direct volume rendering with an interactive 3D texture painting interface to enable quick identification and marking of individual bone structures. The user can paint markers (seeds) directly on the rendered bone surfaces as well as on individual CT slices. Separation of the marked bones is then achieved through the random walks segmentation algorithm, which is applied on a graph constructed from the collective bone segmentation. The segmentation runs on the GPU and can achieve close to real-time update rates for volumes as large as 512^3. Segmentation editing can be performed both in the random walks segmentation stage and in a separate post-processing stage using a local 3D editing tool. In a preliminary evaluation of the tool, we demonstrate that segmentation results comparable with manual segmentations can be obtained within a few minutes.

National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-268818 (URN)
Available from: 2015-12-09 Created: 2015-12-09 Last updated: 2018-05-30Bibliographically approved
Clement, A. M., Nysjö, J., Strand, R. & Ahlberg, P. E. (2015). Brain – Endocast relationship in the Australian lungfish, Neoceratodus forsteri, elucidated from tomographic data (Sarcopterygii: Dipnoi). PLoS ONE, 10(10), Article ID e0141277.
Open this publication in new window or tab >>Brain – Endocast relationship in the Australian lungfish, Neoceratodus forsteri, elucidated from tomographic data (Sarcopterygii: Dipnoi)
2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, article id e0141277Article in journal (Refereed) Published
Abstract [en]

Although the brains of the three extant lungfish genera have been previously described, the spatial relationship between the brain and the neurocranium has never before been fully described nor quantified. Through the application of virtual microtomography (mu CT) and 3D rendering software, we describe aspects of the gross anatomy of the brain and labyrinth region in the Australian lungfish, Neoceratodus forsteri and compare this to previous accounts. Unexpected characters in this specimen include short olfactory peduncles connecting the olfactory bulbs to the telencephalon, and an oblong telencephalon. Furthermore, we illustrate the endocast (the mould of the internal space of the neurocranial cavity) of Neoceratodus, also describing and quantifying the brain-endocast relationship in a lungfish for the first time. Overall, the brain of the Australian lungfish closely matches the size and shape of the endocast cavity housing it, filling more than four fifths of the total volume. The forebrain and labyrinth regions of the brain correspond very well to the endocast morphology, while the midbrain and hindbrain do not fit so closely. Our results cast light on the gross neural and endocast anatomy in lungfishes, and are likely to have particular significance for palaeoneurologists studying fossil taxa.

National Category
Evolutionary Biology Computer Vision and Robotics (Autonomous Systems)
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-267203 (URN)10.1371/journal.pone.0141277 (DOI)000363249300041 ()26492190 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation
Available from: 2015-10-22 Created: 2015-11-19 Last updated: 2018-01-10Bibliographically approved
Nysjö, J. & Hast, A. (2015). Teaching OpenGL and Computer Graphics with Programmable Shaders. In: SIGRAD: . Paper presented at SIGRAD (pp. 1-3).
Open this publication in new window or tab >>Teaching OpenGL and Computer Graphics with Programmable Shaders
2015 (English)In: SIGRAD, 2015, p. 1-3Conference paper, Published paper (Refereed)
National Category
Other Computer and Information Science
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-266125 (URN)
Conference
SIGRAD
Available from: 2015-11-05 Created: 2015-11-05 Last updated: 2018-01-10
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